Highly anti-corrosive metal pigments

ABSTRACT

Highly anti-corrosive thin-platelet like metal pigments having high corrosion resistance and good dispersibility characterized in that the inherent metallic luster of the thin-platelet like metal substrates is maintained without demanding the original surface smoothness are provided. The highly anti-corrosive thin-platelet like metal pigments comprising, on the surface of thin-platelet like metal substrates treated with phosphoric acid compounds and/or boric acid compounds, one or more coated layers containing one or more hydrated metal oxides of one or more metals selected from the group consisting of silicon, aluminum, zirconium, titanium and tin.

[0001] Highly anti-corrosive thin-platelet like pigment, the preparingmethod of the same and the interference colored pigments having metallicluster of which base is the same.

FIELD OF THE INVENTION

[0002] The present invention relates to novel highly anti-corrosivethin-platelet like metal pigment the preparing method of the same,interference colored pigments having a metallic luster of which base isthe same, and use of the same, etc.

BACKGROUND OF THE INVENTION

[0003] Commercially available pearl-luster pigments which usethin-platelet like mica substrates coated with highly refractive metaloxides (called “interference color layer” hereinafter) such as titaniumoxide etc. to exhibit color through interference are well known.However, since the mica is semi-transparent, their reflectivity is low;therefore, expression of interference color by action of interference isnot fully achieved. Thus there appear the interference colored pigmentswhere metal which is opaque and has a high optical reflectance is usedas thin-platelet like substrate and an interference color layer (such astitanium oxide, etc) is coated on its surface (forex, JP (A) Hei.1-110568, JP (A) Hei. 2-669, etc). In these interference coloredpigments, the interference color is layer indirectly coated by means ofthe so-called sol-gel method avoiding an aqueous water treatment, sincethin-plate like metal substrate have a disadvantage that they can easilyreact with water and easily be oxidized.

[0004] Further, goniochromatic pigments (multi-chromatic interferencecolored pigments) has also been known, wherein on the surface ofthin-platelet like metal substrate, the first coating layer is formedusing hydrated silicon oxide (as an example of a substance having a lowrefractive index) by the so-called Sol-Gel method, then other metaloxide having a high refractive index is coated thereon by vapor phasereaction and repeated too give a lure charge (color travel effect) dueto changes in viewing angle (ex. JP (A) Hei. 8-209024, JP (A) Hei.8-302237, JP (A) Hei. 9-124971).

[0005] Moreover, in order to obtain a highly anti-corrosive layer(passivation layer), it has been known that there were a product whichis treated with phosphoric acids, etc, (e.g. DE 19836810.0 etc.), aproduct which is treated with organic phosphoric acids (e.g. JP (A) Hei.3-74472, JP (PCT) 2001-502375, etc.), a product which is treated onlywith silica (e.g. JP (A) Hei. 8-209025; US. Pat. No. 2,885,366 and U.S.Pat. No. 3,954,496; etc.), a product where a treatment with containingvolatile phosphorus compounds and volatile nitrogen containingorganosilicon compounds by the vapor phase method is carried out (JP (A)Hei. 7-292279), and so forth.

[0006] However, in these conventional methods there is the disadvantagethat expensive raw materials have to be used or that the inherentsmoothness of the surface of thin-platelet like metal substrate is notmaintained but is deteriorated or the dispensability of particles isinsufficient resulting in irregular reflection whereby the reflectedlight on the surface of thin-platelet metal can not be adequatelyutilized. Accordingly, even when the upper interference color layer isfurther coated thereon it is not possible to sufficiently achieve theexpression of the interference color.

[0007] In particular, because the anti-corrosive property to acidicaqueous solution is insufficient, it is not possible to carry out thetreatment in an aqueous system where the cost is low and the operationis easy in terms of facilities thereon. Namely, it is not possible toadopt a method in which hydrated metal oxides obtained by neutralhydrolysis using water-soluble metal salts and alkali or by a thermalhydrolysis of water-soluble metal salts in an aqueous system, arecoated, filtered, dried and, if desired, calcined (this will be definedas a wet-process method” as a whole including the description in theclaims). In addition, as mentioned above, smoothness and denseness ofthe surface to which the anti-corrosive layer is coated are notsufficient and, further the affinity between the hydrated metal oxidelayers constituting such an anti-corrosive layer and the hydrated metaloxide layer constituting the interference color layers coated thereon isnot sufficient, whereby it is impossible to achieve a homogenity anddenseness of the hydrated metal oxide layer constituting theinterference color layer; whereby, interference color having a highcoloration can not be exhibited.

[0008] In other cases such as the adoption of vapor phase method (e.g.in JP (A) Hei. 8-209024, JP (A) Hei. 8-302237, JP (A) Hei. 9-124971,etc.), there are disadvantage that production facilities are expensive,volatilizing temperature of the method used in restricted(JP(A)7-292279), whereby in general more strict reaction control isrequired than an aqueous phase reaction, etc. Thus there has been ademand for utilizing the above-mentioned conventional method which isso-called wet-process method.

SUMMARY OF THE INVENTION

[0009] [Object of the Invention]

[0010] Thus, an object of the present invention is to provide highlyanti-corrosive thin-platelet like metal pigments having high corrosionresistance and good dispersibility, wherein the inherent metallic lusterof thin-platelet like metal substrate is maintained without damaging theoriginal surface smoothness of thin-platelet like metal substrate.Another object of the present invention is to provide an interferencecolored pigment having a metallic luster, a high interference colorationand a color travel effect wherein it is possible to adopt the so-calledwet process method for coating hydrated metal oxides onto the surface ofa highly anti-corrosive thin-platelet like metal pigment even when in anacidic aqueous solution.

[0011] [Means for Achieving the Object of the Invention]

[0012] In order to solve the above-mentioned problems, the inventors ofthe present invention have carried out eager investigations and foundthat highly anti-corrosive metal pigment having coated layer containinghydrated metal oxide on the surface of thin-platelet like metalsubstrate treated with phosphoric acids compounds and/or boric acidcompounds is able to solve the above-mentioned problems whereupon thepresent invention has been accomplished.

[0013] Thus, the present invention relates to highly anti-corrosivethin-platelet like metal pigments comprising, on the surface ofthin-platelet like metal substrates treated with phosphoric acidcompounds and/or boric acid compounds, one or more coatings containingone or more hydrated metal oxides of one or more metals selected fromthe group consisting of silicon, aluminum, tin, zirconium and titanium.

[0014] The invention also relates to the above-mentioned highlyanti-corrosive thin-platelet like metal pigments, wherein thethin-platelet like metal substrates are metallic pigment havingbrilliance.

[0015] The present invention further relates to the above-mentionedhighly anti-corrosive thin-platelet like metal pigments, wherein themetallic pigments having brilliance is any one flame of aluminum flakes,titanium flakes, gold flakes, silver flakes, copper-zinc alloy flakes,stainless steel flakes or bronze flakes.

[0016] The present invention also relates to the above-mentioned highlyanti-corrosive thin-platelet like metal pigments, wherein the hydratedmetal oxides are hydrated silicon oxides.

[0017] The present invention further relates to the above-mentionedhighly anti-corrosive thin-platelet like metal pigments, wherein thehydrated metal oxides are prepared by the sol-gel method.

[0018] The present invention also relates to the above-mentioned highlyanti-corrosive thin-platelet like metal pigments, wherein the sol-gelmethod is performed by hydrolysis of metal alkoxide.

[0019] The present invention further relates to the above-mentionedhighly anti-corrosive thin-platelet like metal pigments, wherein thehydrolysis of the metal alkoxide is performed by using a basic catalyst.

[0020] The present invention also relates to the above-mentioned highlyanti-corrosive thin-platelet like metal pigments, wherein the amount ofphosphoric acids compounds and/or boric acids compounds used, iscorresponding to 0.0001-0.1 g as P₂O₅ and/or B₂O₃per unit surface area(m²) of thin-platelet like metal substrates and the amount of metalcompounds used for preparing a hydrated metal oxide coated layer, iscorresponding to 0.01-1.0 g as metal oxide of SiO₂, Al₂O₃, ZrO₂, TiO₂and SnO₂ per unit surface area (m²) of thin-platelet like metalsubstrates.

[0021] The present invention further relates to the preparing method ofhighly anti-corrosive thin-platelet like metal pigments, wherein,dispersing thin-platelet like metal substrate in the polar organicsolvent, and the method contains a process of

[0022] 1) adding phosphoric compounds and/or boric acids compoundsthereto, stirring it, and accordingly treatiry its substrate,simultaneously or subsequently.

[0023] 2) preparing coated layer of a hydrated metal oxide on thesurface of said substrates by the sol-gel method.

[0024] The present invention also relates to the above-mentionedpreparing method, wherein the sol-gel method is performed by hydrolysisof metal lakeside solution that is dissolved in a polar organic solvent.

[0025] The present invention further relates to the above-mentionedpreparing methods, wherein the metal composing the layer of metal oxidecoating are one or more metals selected from the group consisting ofsilicon, aluminum, zirconium, titanium and tin.

[0026] The present invention also relates to the above-mentionedpreparing method characterized in the metal alkoxide solution is addedafter adding water and a catalyst.

[0027] The present invention further relates to the above-mentionedpreparing method, wherein the metal alkoxide solution and the aqueoussolution containing a catalyst.

[0028] The present invention also relates to the above-mentionedpreparing method, wherein the aqueous solution containing catalyst isadded after addition of the metal alkoxide solution.

[0029] The present invention further relates to the above-mentionedpreparing method, wherein the catalyst is a basic catalyst.

[0030] The present invention also relates to the interference coloredpigments having metallic luster, wherein the surface of the highlyanti-corrosive thin-platelet like metal pigment according to any ofclaims 1 to 8 in further coated with a secondary hydrated metal oxidelayers comprising one or more layers.

[0031] The present invention further relates to the above-mentionedinterference colored pigments having metallic luster, wherein thesecondary of coated layer hydrated metal oxides is prepared by wetprocess method, a chemical vapor deposition process method or a physicalvapor deposition process method.

[0032] The present invention also relates to the above-mentionedinterference colored pigments having metallic luster, wherein thesecondary coated layer of hydrated metal oxides is prepared by wetprocess method.

[0033] The present invention further relates to the above-mentionedinterference colored pigments having metallic luster, wherein thesecondary coated layer of hydrated metal oxides is the coated layercontaining one or more hydrated metal oxides of one or more metalsselected from the group consisting of titanium, aluminum, zirconium,tin, zinc, iron, chromium, cobalt, silicon and boron.

[0034] The present invention also relates to the above-mentionedinterference colored pigments having metallic luster, wherein thesecondary coated layers of hydrated metal oxides are multi-coated layershaving different hydrated metal oxides.

[0035] The present invention further relates to the above-mentionedinterference colored pigments having metallic luster, wherein thesecondary coated layer of hydrated metal oxides are alternativelymulti-coated layer of metal oxide or hydrates having a high refractiveindex and a low refractive index.

[0036] The present invention also relates to the use of theabove-mentioned highly anti-corrosive thin-platelet like metal pigmentor the above-mentioned interference colored pigments having metallicluster in paints, powder coatings, its painting layers, inks, securityprinting inks, plastics, pellets, moldings, and cosmetics.

[0037] The present invention further relates to a composition comprisingthe above-mentioned highly anti-corrosive thin-platelet like metalpigments or the above-mentioned interference colored pigments having ametallic luster in combination with one or more pigments selected fromthe group consisting of organic pigments, inorganic pigments, effectpigments, fillers, and functional pigments.

[0038] The highly anti-corrosive thin-platelet like metal pigments ofthe present invention, have a good anti-corrosive property withoutdeteriorating the smoothness of the surface of metal substrate, andparticularly since hydrogen gas is rarely generated even in an acidicaqueous solution, it is now possible to carry out a coating of hydratedmetal oxide layer by wet process method, which has been said to beunsuitable to a metal substrate.

[0039] As for the highly anti-corrosive thin-platelet like pigments,although the mechanism for the changes in properties resulted by thecombination of the treatment with phosphoric acids compounds and/orboric acids compounds and the preparation of a coated layer containinghydrated metal oxides is not necessarily clear; however, the detainedhighly anti-corrosive thin-platelet like metal pigments can render notonly anti-corrosive property by passivation, but also denseness andsmoothness of the surface which have not been available in conventionalanti-corrosive treatment, and further achieve a good dispersibility ofthe obtained pigments due to the above-mentioned combination.Consequently, when the highly anti-corrosive thin-platelet like metalpigments according to the present invention are used as substrates ofinterference colored pigments, it is possible to obtain dense andhomogeneous coating and interference colored pigments having metallicluster with good dispersibility, since the pigments have a good affinitywith the hydrated metal oxide layer to be coated due to their surface ofdenseness. The pigments obtained as a result thereof have both inherentlaboring of the metal due to the high reflecturance from the surface ofthe thin-platelet substrate and good interference colors due tointerference if the coated hydrated metal oxides layer, resulting inchange of hue (color travel effect) by changing the view angle. Thus itis a novel interference color pigment having a metallic luster, whereinits coloration (chromaticity) surprisingly improved.

BRIEF DESCRIPTION OF THE DRAWINGS

[0040]FIG. 1 shows a comparison of the amount of hydrogen gas in thecase of use of SS5588 was used among the untreated SS5588, SS5588(P) andSiO₂/SS5588(P).

[0041]FIG. 2 shows a comparison of the amount of hydrogen gas in thecase of use of 550N was used among the untreated 550N, 550N(P) andSiO₂/550N(P).

[0042]FIG. 3 shows a comparison of the amount of hydrogen gas in thecase of use of SL800 was used among the untreated SL800, SL800(P) andSiO₂/SL800(P).

[0043]FIG. 4 shows a comparison of the amount of hydrogen gas in thecase of use of 5422NS was used among the untreated 5422NS, 5422NS(P),SiO₂/5422NS(P) and SiO₂/5422NS.

[0044]FIG. 5 shows a comparison of the amount of hydrogen gas in thecase of use of 5422NS was used among the untreated 5422NS, 5422NS(B),SiO₂/5422NS(B) and SiO₂/5422NS.

BEST MODES FOR CARRYING OUT THE INVENTION

[0045] Hereinafter, the present invention will be explained in moredetail together with the preparing method.

[0046] The thin-platelet like metal substrates used in the presentinvention are so-called metallic pigments which contain thin-plateletlike metals and metal alloys.

[0047] The thin-platelet like metal substrates used in the presentinvention preferably have an average particle diameter of 2-100 μm andan average thickness of 0.05-5 μm, more preferably they have an averageparticle diameter of 5-50 μm and an average thickness of 0.1-2 μm, andeven more preferably they have an average particle diameter of 5-30 μmand an average thickness of 0.1-2 μm.

[0048] Specific examples of flakes include aluminum flakes, titaniumflakes, gold flakes, silver flakes, copper-zinc alloy flakes, ironflakes, bronze flakes, stainless steel flakes, aluminum bronze flakes,flakes of various aluminum alloys, flakes of various titanium alloys,etc. Preferred flakes include aluminum flakes, titanium flakes, goldflakes, silver flakes, copper-zinc alloy flakes, stainless steel flakes,bronze flakes, etc.; even more preferred flakes include the widely soldbrilliant metallic pigments such as aluminum flakes (from e.g.Silberline; Showa Aluminum Co., Ltd.; Toyo Aluminum Co., Ltd.; AsahiKasei Metals Co., Ltd.; Eckart-Werke; etc.), titanium flakes, stainlesssteel flakes, etc. of which there is a stable supply commerciallyavailable; and most preferred are aluminum flakes.

[0049] Among these, thin-platelet like metal substrates commerciallyavailable in various states may be used, such as those substrate flakesthat have already been suspended in an organic solvent to preventoxidative corrosion caused by the moisture contained in the air (e.g.,pigment pastes suspended in mineral spirit, etc.), those substratesthat, for the purpose of leafing or for improving dispersibility, havebeen treated with different types of surface treatment agents and havebeen suspended in an organic solvent and those substrate on whosesurface an oxidation protection film (passivation film, i.e. surfaceoxidized thin-film layer) has been applied beforehand. Regarding theobject of the present invention, its effect is brought out particularlyby metal flakes having high corrosiveness, as long as the surface islargely free from oxidation; hence the use thereof is preferred.

[0050] For example, those substrates with high corrosiveness such asaluminum flakes which are available in the market at the state ofsuspension in an organic solvent before being handled and thosesubstrates which have been treated with different surface treatmentagents and have been suspended in an organic solvent are particularlyrecommended for use in the present invention.

[0051] When using thin-platelet like metal substrates which have beensubjected beforehand to an anti-corrosive (passivation) treatment andthose alloy substrates, there is no need to perform the treatment basedon the present invention simply to confer corrosion resistance; however,apart from improving the durability of the corrosion protection, theanti-corrosive layer according to the present invention, different fromthe above-mentioned anti-corrosive treatments, is also effective forforming a smooth, homogeneous and dense and dense layer of hydratedmetal oxides thereafter.

[0052] Next, a suspension is prepared with a polar organic solvent inwhich these thin-platelet like metal substrates are dispersed. Accordingto the present invention, the suspension of a polar organic solvent isdefined as the material that can be prepared as follows:

[0053] (1) thin-platelet like metal substrates suspended in an organicsolvent are suspended, as they are, in a polar organic solvent to obtaina suspension with the desired concentration;

[0054] (2) thin-platelet like metal substrates as solid parts (theflakes are not completely dried so that some adhering solvent remains toprevent direct contact with air and moisture) are retrieved beforehandby filtration and centrifugal separation of the organic solvent, and arethen suspended in a polar organic solvent to obtain a suspension withthe desired concentration;

[0055] (3) if the thin-platelet like metal substrates have already beentreated with a surface treatment agent, the surface treatment agent iswashed and removed using a polar organic solvent, and after filtration,the substrates are again suspended using a polar organic solvent toobtain a suspension with the desired concentration;

[0056] (4) if the thin-platelet like metal substrates are available inthe market as the state of the powder which has been subjected to apassivation treatment, they are suspended, as they are, in a polarorganic solvent to obtain a suspension with the desired concentration.

[0057] Examples of polar organic solvents used in the present inventioninclude ketones such as acetone, methyl ethyl ketone (MEK), methylisobutyl ketone (MIBK), etc.; alcohols with an alkyl group having 1-10carbon atoms; tetrahydrofuran (THF); dimethylformamide (DMF);dimethylsulfoxide (DMSO); dioxanes; polyols and cellosolve solvents.Among these, alcohols which are in the liquid state at normaltemperatures may be selected; examples of which include e.g. methanol,ethanol, isopropylalcohol, butanol, isobutanol, pentanol, hexanol,heptanol, octanol, isooctanol, nonanol, decanol and isomers thereof.Examples of preferred alcohols include ethanol, isopropylalcohol,butanol, isobutanol because they are inexpensive and easy to handle atnormal temperature. Especially isopropylalcohol and ethanol etc. areused because of their low volatility and low cost. Moreover, thesesolutions may also be appropriately mixed. Further, if metal alkoxide isused for forming the hydrated metal oxide layer (defined as the “secondstage coating” in the present specification), alcohols having a highcompatibility with metal alkoxides are selected for the polar organicsolvent used in the present invention. Naturally, an appropriateselection needs to be made also in consideration of the compatibilitywith the phosphoric acid compounds and boric acid compounds used. Froman economic point of view it is desirable to use the same polar organicsolvent for the treatment with phosphoric acid compounds and/or boricacid compounds (defined as the “first stage treatment” in the presentrequirement) and for the second stage coating reaction; however, it isalso possible to use different solvents for the respective treatment andcoating stages when taking into consideration reaction efficacy and thecompatibility with the reactants used at the respective reaction stages.Further, the polar organic solvent used for removing the surfacetreatment agents described in (3) above is appropriately selected inconsideration of its compatibility with the surface treatment agent.

[0058] The concentration of the suspension of a polar solvent in whichthe thin-metallic like metal substrates have been suspended can beappropriately changed according to the density of the those metalsubstrates used, the performance of the agitator and the viscosity ofthe solvent.

[0059] The treatment with phosphoric acid compounds and/or boric acidcompounds in the present invention corresponds to a pretreatment forforming a hydrated metal oxide layer which is treated simultaneously orsubsequently; i.e., by combining this treatment with the second stagecoating the object of the present invention is achieved.

[0060] The highly anti-corrosive thin-platelet like metal pigmentsobtained are one part of the present invention (claims 1-8)characterized in that good anti-corrosive properties, good brillianceand good dispersibility with little particle agglomeration are achieved.

[0061] In the present invention, the first stage treatment or the secondstage coating cannot, each on its own, achieve the objects of thepresent invention, i.e. corrosion resistance and the homogeneous anddense hydrated metal oxides obtained by the wet process method performedthereafter. Further, even if the order is inverted, and the first stagetreatment is performed after the second stage coating, it is notpossible to obtain an effect superior to that obtained by the secondstage coating on its own.

[0062] Consequently, it is important that the hydrated metal oxide layeris formed on a surface treated with phosphoric acid compounds and/orboric acid compounds, and as long as this constitution is achieved it isalso possible to perform the first stage treatment and the second stagecoating simultaneously or subsequently; however, is preferred to performfirst the first stage treatment and then the second stage coating toassure that said constitution is achieved.

[0063] Hereinafter, the first stage treatment will be explained.

[0064] The treatment with phosphoric acid compounds and/or boric acidcompounds is performed by adding the phosphoric acid compounds and/orboric acid compounds to the suspension of a polar organic solvent inwhich thin-platelet like metal substrates have been suspended.

[0065] Taking into consideration good anti-corrosive property,dispersibility and economic factors, the amount of phosphoric acidcompounds and/or boric acid compounds used, preferably is an amountcorresponding to 0.0001-0.1 gas P₂O₅ and/or B₂O₃per unit surface area(m²) of thin-platelet like metal substrates, even more preferably is anamount corresponding to 0.0002-0.08 g and still more preferably is anamount corresponding to 0.0005-0.05 g. Thus, the amount used for thistreatment is naturally determined in view of the unit surface area ofthe thin-platelet like metal substrates; i.e. a small amount is usedwhen the particle diameter is big, while a large amount is required ifthe particle diameter is small.

[0066] When using phosphoric acid compounds and boric acid compounds inan aqueous solution, it is preferred to determine the amount of water soas not to become excessive while taking into consideration the amountused (consumed) in subsequent processes and so that the surfaceroughness of the raw material of the thin-platelet like metal substratesdoes not increase. Further, it is also possible to use these solvents ofphosphoric acid compounds and boric acid compounds with the watermentioned before dissolved together as one solvent with the polarorganic solvents subsequently used for preparing the suspension ofthin-platelet like metal substrates. In any case, the polar organicsolvent used is appropriately selected while taking into considerationits affinity and compatibility the thin-platelet like metal substrateswith phosphoric acid compounds and boric acid compounds.

[0067] Examples of phosphoric acid compounds used in the presentinvention include phosphoric acid, orthophosphoric acid, metaphosphoricacid, tripolyphosporic acid, hypophosphorous acid, phosphorous acid,various polyphosphates thereof, various phosphates thereof having atleast one OH group, organic acidic phosphoric acid esters (e.g., methylacid phosphoric acid, butyl acid phosphoric acid, dibutyl acidphosphoric acid, monobutyl acid phosphoric acid, 2-ethylhexyl acidphosphoric acid, bis-2-ethylhexyl acid phosphoric acid, isodecyl acidphosphoric acid, diisodecyl acid phosphoric acid, etc.), organic acidicphosphorous acid esters (e.g., dibuthyl hydrogen phosphite etc.),2-methacryloyloxyethyl acid phosphoric acid, hydroxyethanediphosphonicacid {CH₃C(OH)(PO₃H₂)₂}, phosphoric acid bis[2-(N-propylperfluorooctylsulfonyl amino)ethyl]ester, perfluoroalkylethyl phosphoricacid ester (e.g., (RfCH₂CH₂O)P(O)(OH)₂, (RfCH₂CH₂O)₂P(O)(OH),characterized in that Rf represents a perfluoroalkyl group ofCF₃(CF₂)₆₋₁₇). The terms “acidic” and “acid” in the above-mentionedphosphoric acid compounds mean that such as phosphoric acid compoundshas at least one OH group. Further, by selecting an appropriate organicester group as bonded group of the phosphoric acid compounds, it ispossible to increase the affinity with the polar organic solvent used inthe subsequent reaction.

[0068] Examples of boric acid compounds used in the present inventioninclude boric acid, boric acid ammonium, metaboric acid, metaboric acidlithium, metaboric acid ammonium, hypoboric acid, hypoboric acidammonium, etc.

[0069] The treatment of the highly anti-corrosive thin-platelet likemetal pigments of the present invention can be performed by phosphoricacid compounds, by boric acid compounds or by both phosphoric acid andboric acid compounds, etc., as long as the object of the presentinvention is achieved.

[0070] After the treatment has been completed, the suspension can beused as it is or the solid parts can be retrieved by filtration toperform the subsequent second stage coating reaction.

[0071] Hereinafter, the second stage coating reaction will be explained.

[0072] Considering that metal substrates are used, it is preferred toperform the coating of the hydrated metal oxides by a sol-gel method;among these, a method using metal alkoxide as metal compound to behydrolyzed is preferred.

[0073] The suspension obtained by the first stage treatment reaction canbe used as it is, or the solid parts retrieved by filtration can againbe dispersed in a polar organic solvent, which may be identical to ordifferent from the one of the first stage treatment reaction, to preparea suspension. The second stage coating, requiring the presence of acatalyst, is formed by adding metal compounds and a predetermined amountof water necessary for hydrolysis. It is possible to use an acidiccatalyst for the hydrolysis; however, for forming a homogeneous anddense treatment coated layer, ammonium compounds and/or amino-compoundsare preferred. The use of a basic catalyst is characteristic of thepresent invention.

[0074] Taking into consideration corrosion resistance and economicfactors, the amount of metal alkoxide or other metal compounds usedaccording to the present invention, calculated as SiO₂, Al₂O₃, ZrO₂,TiO₂ and SnO₂, preferably is an amount corresponding to 0.01-1.0 g perunit surface area (m²) of thin-platelet like metal substrates, even morepreferably is an amount corresponding to 0.02-0.8 g and still morepreferably is an amount corresponding to 0.05-0.5 g.

[0075] Examples of metals used for the hydrated metal oxides for formingthe highly anti-corrosive thin-platelet like metal pigments according tothe present invention include silicon, aluminum, zirconium, titanium andtin, which as hydrated metal oxides are transparent. These hydratedmetal oxides can be oxides of one type of metal or composite oxides oftwo or more types of metal; however, taking into consideration theirhigh transparency, their low index of refraction and the low cost of theraw material, hydrated silicon oxides are particularly preferred.

[0076] Moreover, it is also possible to form multi-layers of hydratedmetal oxide layers comprising one or more kinds of these hydrated metaloxides. Examples of raw materials used at this stage include metalalkoxides and organic acid salts.

[0077] Specific examples of silicon alkoxides used in the presentinvention include e.g. tetramethoxy silicate, tetraethoxy silicate,tetrapropoxy silicate, tetraisopropoxy silicate, tetrabutoxy silicate,tetrapentoxy silicate, tetrahexoxy silicate, so-called silane couplingagents (e.g., alkoxy silicate having an alkyl group, alkoxy silicatehaving an aminoalkyl group, alkoxy silicate having a glycidylalkylgroup, etc.). Each of them may be used either solely or in combination.When using a silane coupling agent, a desired surface modification canbe designed.

[0078] Specific examples of aluminum alkoxides include e.g. aluminumtriethoxide, aluminum tri-iso-propoxide, aluminum tri-sec-butoxide,aluminum ethylacetate di-iso-propoxide, etc.

[0079] Specific examples of zirconium alkoxides include e.g. zirconiumtetraethoxide, zirconium tetra-n-propoxide, zirconiumtetra-iso-propoxide, zirconium tetra-n-butoxide, etc.

[0080] Specific examples of titanium alkoxides include titaniumtetraethoxide, titanium tetra-n-propoxide, titanium tetra-iso-propoxide,titanium tetra-n-butoxide, etc.

[0081] Specific examples of tin alkoxides include e.g. tintetraethoxide, tin tetra-iso-propoxide, etc.

[0082] As polar organic solvents for the second stage coating reaction,it is preferred to use alcohols constituting metal alkoxides.

[0083] The ammonium compounds and/or amino compounds that can be used asbasic catalysts in the second stage coating reaction, in addition toserving as catalyst for hydrolyzing the metal alkoxide by the sol-gelmethod, are also useful for forming a homogeneous and dense coated layerof hydrated metal oxides.

[0084] Specific examples of ammonium compounds used in the presentinvention include e.g. ammonia, ammonium carbonate, ammonium phosphoricacid, ammonium acetate, ammonium oxalate, ureas, etc.; and specificexamples of amino compounds include e.g. γ-aminopropyl triethoxysilicate, triethanolamine, diethanolamine, and their salts. Among these,γ-aminopropyl triethoxy silicates etc. combine in the same molecule thetwo functions of the above-mentioned silicon alkoxides and the aminocomponent, hence they are appropriately selected to obtain the desiredproperties.

[0085] From the point of view of reaction rate, anti-corrosive propertyand the amount of hydrated metal oxides to be coated etc., the amount ofthese basic catalysts, i.e. the ammonium and/or amino compounds,preferably is an amount corresponding to 0.01-100 mol, and especiallypreferably an amount corresponding to 0.1-30 mol per 1 mol of metalalkoxide compounds.

[0086] Any of the following methods may be adopted for adding water insaid sol-gel method:

[0087] (1) adding the amount of water necessary for hydrolysis to thesuspension obtained by the first stage treatment reaction before addinga solution of metal alkoxides,

[0088] (2) adding water and metal alkoxide separately and at the sametime to the suspension obtained by the first stage treatment reaction,and

[0089] (3) adding metal alkoxide to the suspension obtained by the firststage treatment reaction before adding water.

[0090] More precisely, the following methods may be adopted for thesuspension after the first stage treatment:

[0091] a. adding a predetermined amount of water and a catalyst, thenadding a separately prepared metal alkoxide solution dissolved in apolar organic solvent,

[0092] b. adding a separately prepared aqueous solution of a catalystand a predetermined amount of water and further separately preparedmetal alkoxide solution dissolved in a polar organic solvent separatelyand simultaneously, and

[0093] c. adding a predetermined amount of metal alkoxide before addinga catalyst and a predetermined amount of water provided separately.

[0094] Among these, the method in which water and the metal alkoxidesolution are separately added at the same time when the speed of thehydrolysis reaction is high is preferred in that a state of excessivewater during the hydrolysis reaction can thus be avoided.

[0095] A high reaction temperature is preferred to increase the speed ofthe hydrolysis reaction; however, it is appropriately determined inconsideration of the boiling point of the polar organic solvent usedetc. When operating at a temperature in the vicinity of the boilingpoint, the solution can be cooled and refluxed by using a condenser.

[0096] Thus, the highly anti-corrosive thin-platelet like metal pigmentsaccording to the present invention can be obtained by filtering,separating and drying the solid parts of the suspension of a polarorganic solvent obtained from the second stage treatment.

[0097] The treatment by phosphoric acid compounds or boric acidcompounds and the combination of different types of hydrated metaloxides forming the hydrated metal oxide layer are determined inconsideration of the transparency of the highly anti-corrosivethin-platelet like metal pigments to be obtained, the amount of lightreaching to the thin-platelet like metal substrates beneath thetreatment layers, the amount of reflected light depending thereon, thedesired coloring properties, etc.; Among about it is preferred to form alayer of hydrated silicon oxides generated by hydrolyzing siliconalkoxide on the surface of thin-platelet like metal substrates treatedwith phosphoric acid compounds and/or boric acid compounds.

[0098] The highly anti-corrosive thin-platelet like metal pigmentsaccording to the present invention have good anti-corrosive propertyand, even when left for 2 hours in a heated hydrochloric aqueoussolution with a pH of 1.8, hydrogen gas was rarely generated.

[0099] The term “hydrated silicon oxide”, as used in the presentspecification, denotes compounds in which silicon oxides, hydrates ofsilicon oxides and hydroxyl group bonded silicon oxides and other bondedstates are present as an inclusive whole. Similarly, the term “hydratedmetal oxides”, as used in the present specification including theclaims, denotes, as compounds obtained by drying and, if desired,calcining hydrolyzed metal salts and metal compounds such as metalalkoxide etc., and compounds in which metal oxides, hydrates of metaloxides and hydroxyl group bonded metal and other bonded states arepresent as an inclusive whole.

[0100] The highly anti-corrosive thin-platelet like metal pigments ofthe present invention are mainly used as pigments having metallic lusterparticularly having brilliance, for paints, inks, plastics, etc. Sincethey can be used in aqueous system or a powder system, they areparticularly preferred, from the environmental point of view and forimproving the work environment, as powder coatings and as water-bornepaints and inks. These highly anti-corrosive thin-platelet like metalpigments, depending on their intended use, can be used to carry out e.g.treatments to light resistance, water and weather resistance requiredfor applications as automobile paints (e.g. according to JP (A) Sho.63-130673, JP (A) Hei. 1-292067, etc.), e.g. treatments for high planeorientation properties (leafing) required in the painting and printingfields (e.g. according to JP (A) 2001-106937, Japanese PatentApplication Hei. 11-347084, etc.), water-borne treatments forwater-based paints or inks (e.g. according to JP (A) 8-283604, etc.),silicon treatment for improving dispersibility and hydrogenpolysiloxanetreatment for improving the hydrophoric and oil phobic properties forapplications in the cosmetics field, surface treatments for weld-lineprevention when used as resin (e.g. according to JP (A) Hei. 3-100068),and different treatments for improving dispersibility.

[0101] The highly anti-corrosive thin-platelet like metal pigments inthe present invention are indispensable for and required as base for thenovel interference colored pigments having metallic luster according tothe present invention described below; and the two treatment stagesdescribed above are not merely for imparting high anti-corrosion to thesurface of the thin-platelet like metal substrates, they are alsoimportant for achieving a dense and homogeneous hydrated metal oxidelayer subsequently formed on the upper layer thereof. Namely, only byforming the highly anti-corrosive layer obtained by the treatmentsdescribed above is it possible to pass to the subsequent hydrated metaloxides coating process by the wet process method and to easily coathydrated metal oxides on the upper layer of the anti-corrosive layer.

[0102] Hereinafter, the interference colored pigments having metallicluster (claims 16-21) of the present invention which are based on thehighly anti-corrosive thin-platelet like metal pigments of the presentinvention and which are obtained by further secondary coating ofhydrated metal oxides comprising one or more layers are described. Inthe present invention, the secondary coating of hydrated metal oxides onthe surface of the anti-corrosive thin-platelet like metal can also beformed by the vapor phase method (chemical vapor deposition (CVD) andphysical vapor deposition (PVD)) and the sol-gel method; however, it ispreferred to use the wet process method which, in contrast to the vaporphase and sol-gel methods, has no limitations with regard to the rawmaterial and production facilities and which is an easy to operatesimple process with a wide range of applications.

[0103] It is a major characteristic of the present invention that atthis stage the so-called wet process method can be adopted because ofthe excellent anti-corrosive properties.

[0104] Metals constituting the secondary coating of hydrated metaloxides for generating interference colors, include not only titanium,aluminum, zirconium, tin, zinc, iron, chromium and cobalt, also includesilicon, boron, etc. Hydrated metal oxides of titanium, zirconium, tin,zinc, silicon, boron, etc. having transparency and hydrated metal oxidesof iron, chromium, cobalt, etc. having a colored transparency areappropriately selected for use. Among these, titanium is preferred inconsideration of its high index of refraction and iron is preferred inconsideration of the interference color having its inherent color.

[0105] The interference colored pigments having metallic luster of thepresent invention can be obtained by using water-soluble metal saltswith the sol-gel method on their own or in combination (i.e. as hydratedcomposite metal oxides), in a multilayer coating characterized in thatthe material is changed for each layer (e.g. in the order of hydratedtitanium oxides—hydrated iron oxides, etc.), or in a multilayer coatingcharacterized in that hydrated metal oxide layers with a high refractiveindex (representative of this type are e.g. hydrated titanium oxides,hydrated zirconium oxides, etc.) alternate with hydrated metal oxidelayers with a low refractive index (e.g. hydrated aluminum oxides,hydrated silicon oxides, hydrated boron oxides, etc.), etc.

[0106] A definition of the wet process method, as used in the presentinvention, has been given before, more precisely, the method consistsof, in a an aqueous system and

[0107] (1) In the case of neutralization hydrolysis, selecting thedesired water-soluble metal salt (e.g., nitrate salt, sulfate salt,chloride, acetate salt, etc.) and predetermined the prescribed amount ofaqueous solution, while separately preparing an alkaline solution,dropping these into a suspension of highly anti-corrosive thin-plateletlike metal pigments which is the base obtained beforehand whilemaintaining a predetermined pH, forming a hydrolyzed layer and,thereafter, washing, filtering, drying and, if desired, calcining;

[0108] (2) In the case of thermal hydrolysis, adding the predeterminedamount of the desired water-soluble metal salt to a suspension of highlyanti-corrosive thin-platelet like metal pigments which is the baseobtained beforehand and, by heating, forming a hydrolyzed layer and,thereafter, washing, filtering, drying and, if desired, calcining.

[0109] Moreover, as a variation of the method by neutralizationhydrolysis (1), a method using, instead of the alkaline aqueoussolution, acetoamide and urea producing alkalinity through heating, (theso-called “homogeneous precipitation method”) can also be mentioned.Thus, the interference colored pigments having metallic luster, whichare the object of the present invention, can be obtained by selecting atoptionally water-soluble metal salts, using them on either solely or incombination and by changing the time at which they are introduced to thesuspension.

[0110] More specifically, the metallic luster interference coloredpigments having metallic luster of the present invention can beprepared, in the case of a coating of a single hydrated metal oxide, byselecting one water-soluble metal salt such as titanium, zirconium, tin,zinc, iron, chromium, cobalt, etc. for coating the hydrated metal oxideby means of neutralization hydrolysis under alkaline conditions or bythermal hydrolysis; in the case of a coating of composite metals, bymixing plural metal salts for coating the hydrated composite metaloxides by neutralization hydrolysis or by thermal hydrolysis; or, in thecase of a multilayer coating, by sequentially adding the different metalsalts for coating sequential layers of hydrated metal oxides; and by,thereafter, washing, filtering, drying and, if desired, calcining. Whenforming, according to the present invention, a multilayer coating withalternate layers, aqueous solutions of metal salts, forming the relativehigh refractive index layers (mentioned before) and low refractive indexlayers (mentioned before), are alternately dropped, in the same way,into the base, i.e. the suspension of highly anti-corrosivethin-platelet like metal pigments, sequentially coating the hydrolatesthereof. The color chromaticity of the interference colored pigmentshaving metallic luster obtained by forming an alternate layer multilayercoating is improved through the accumulation of interferences when thereflection/transmission of light at the boundary of each layer isrepeated by the alternate coating of plural layers alternatelycontrolling the optical thickness (for details refer to WO 98/5301 1).The color chromatiaty of the interference colored pigments havingmetallic luster obtained by forming an alternate layer multilayercoating have a high chromatiaty which cannot be obtained by singlehydrated metal oxide coating having high refractive index using a singlemetal.

[0111] In the present invention, if hydrated titanium oxides areincluded in the constituent elements of the interference color layer, itis possible to change them to rutile-type by using a tin compound orother rutile agents for increasing the refractive index of the hydratedtitanium oxide crystals. The coloring properties are improved by thechange to a rutile-type titanium oxide.

[0112] The interference colored pigments having metallic luster obtainedby the present invention produce the so-called color travel effect(characterized in that the observed colors vary with the observationangle), combining the inherent color of the metal (masstone) and theinterference colors, because the anti-corrosive layer is homogeneous anddense and the high refractive index hydrated metal oxides coated on thesurface thereof have a high homogeneity and denseness.

[0113] In these interference color layers, known colored or blackinorganic and organic pigments of ultrafine particles can be included toproduce interference colored pigments having metallic luster maintainingthe inherent colors (masstones) of these pigments while generatinginterference colors. This has only become possible by adapting the easyto operate wet process method, which makes it possible to extend thesepigments to various color ranges and to broaden the range ofapplications.

[0114] By performing different types of additional surface treatments,the metallic luster interference colored pigments having metallic lusterobtained according to the present invention meet with the qualityrequired for the applications for which these treatments are used. Forexample, it is possible to carry out treatments to light resistance,water-and weather resistance required for applications as automobilepaints (e.g. according to JP (A) Sho. 63-130673, JP (A) Hei. 1-292067,etc.), e.g. treatments to impart high plural orientation properties(leafing) required in the painting and printing fields (e.g. accordingto JP (A) 2001-106937, Japanese Patent Application Hei. 11-347084,etc.), water-borne treatments for water-borne paints or inks (e.g.according to JP (A) 8-283604, etc.), silicon treatment for improvingdispersibility and hydrogenpolysiloxane treatment for improvinghydropholic and oilpholic properties for applications in the cosmeticsfield, surface treatments for weld-line prevention when used as resin(e.g. according to JP (A) Hei. 3-100068), and different treatments forimproving dispersibility.

[0115] Hereinafter, the uses of the highly anti-corrosive thin-plateletlike metal pigment prepared by the present invention and theinterference colored pigments having metallic luster using the same asbase will be described. The highly anti-corrosive thin-platelet likemetal pigments and the interference colored pigments having metallicluster obtained according to the present invention can be used invarious applications such as paints, printing inks, resin compositions,cosmetics, etc. Specific examples thereof will be given below. Althoughnot particularly described, highly anti-corrosive thin-platelet likemetal pigments and interference colored pigments having metallic lusteraccording to the present invention used in the following examplesinclude the product prepared by performing the above-mentioned varioustreatments.

[0116] Use for paints

[0117] Examples of use in paints are those of organic solvent-typepaints, NAD paints, water-borne paints, emulsion paints, colloidalpaints and powder coating. The pigments of the present invention can bemixed in a proportion of 1-100 wt % to the paint resins as solid parts.A proportion of 1-70 wt % is preferred. A proportion of 1-20 wt % isparticularly preferable. For improving the dispersibility, the surfaceof the pigments in the present invention can be treated with a silanecoupling agents and a titanium coupling agents. Examples of resincomponents for the paints in the present invention are acrylate resins,alkyd resins, unsaturated polyester resins, amino resins, melamineresins, polyurethane resins, epoxy resins, polyamide resins, phenolresins, cellulose resins, vinyl resins, silicone resins, fluorineresins, etc. These resins may be used alone or in combination of two ormore.

[0118] In water-borne paint, resin of an emulsion type containingcross-linking resin by acrylate melamine resins may be exampliefied.

[0119] Examples of mixtures and admixtures include combination pigments,organic pigments, inorganic pigments, dripping preventers, viscosityadjusting agents, sedimentation preventers, cross-linking promoters,curing agents, leveling agents, defoaming agents, plasticizers,antiseptic agents, antifungal agents, ultraviolet stabilizers, fillers,etc. Examples of combination pigments are titanium dioxide, calciumcarbonate, clay, talc, barium sulfate, white carbon, chromium oxide,zinc oxide, zinc sulfide, zinc powder, metal powder pigments (such as.,aluminum flakes, colored aluminum flakes, stainless steel flakes,titanium flakes, etc.), iron black, yellow iron oxide, red iron oxide,chrome yellow, carbon black, molybdate orange, Prussian Blue,ultramarine blue, cadmium type pigments, fluorescent pigments, solubleazo dyes, insoluble azo dye, condensed azo dye, phthalocyanine pigments,condensed polycyclic pigments, composite oxide pigments, graphite, mica(e.g., white mica, gold mica, synthetic mica, fluorine tetra siliconmica, etc.), metal oxide coated mica (such as, titanium oxide coatedmica, titanium dioxide coated mica, (hydrated) iron oxide coated mica,mica coated with iron oxides and titanium oxides, mica coated with lowerordered titanium oxides), metal oxide coated graphite (e.g., titaniumdioxide coated graphite, etc.), thin-platelet like alumina, metal oxidecoated alumina (e.g., dioxide coated alumina, iron oxide coatedthin-platelet like alumina, Fe₂O₃ coated thin-platelet like alumina,Fe₃O₄ coated thin-platelet like alumina, interference color metal oxidecoated thin-platelet like alumina, etc.), MIO, metal oxide coated MIO,metal oxide coated silica flakes metal oxide coated alumina, metal oxidecoated glass flakes called as optical effect pigments, photochromicpigments, thermochromic pigments, holographic pigments called asfunctional pigments, etc. By combining these and other pigments, novelhue and chromaticity can be improved. These paints can be applied towood, plastic, metal sheets, glass, ceramic, paper, film, sheeting,translucent films of reflector for LCDs, etc. Examples of uses forpaints include automobiles, buildings, marine vessels, electrichousehold appliances, canned goods, industrial equipment, traffic signs,plastic, household goods, etc.

[0120] Examples of the structure of the coated film exemplified e.g. afilm coated in the order of a base coat layer, middle coat layer, layercontaining the pigments of the present invention and clear layer, and astructure in the order of base coat layer, middle coat layer comprisingthe pigments of the present invention and clear layer, etc.; however,the structure of the coated film is not limited thereto.

[0121] Examples of the method for forming the coated film areone-coat/one-bake, two-coat/one-bake, two-coat/two-bake,three-coat/one-bake, three-coat/two-bake, three-coat/three-bake.Examples of coating methods include electrostatic coating, spraycoating, airless coating, roll coating, immersion coating, etc.

[0122] Use for Printing Inks

[0123] Examples of use in printing inks include relief printing ink,lithographic printing ink, intaglio printing ink, ink for metal plates,radiation curable ink, UV ink, EB ink, flexo ink, screen ink, offsetink, gravure ink, etc. and water-borne ink thereof, etc. The pigments ofthe present invention can be mixed in a proportion of 1-100 wt % to theresins, as solid parts, in the ink. A proportion of 1-70 wt % ispreferred. And a proportion of 1-20 wt % is particularly preferred.Moreover, the surface of the pigments in the present invention can betreated with silane coupling agents and titanium coupling agents, etc.Examples of resin components include e.g. rosin maleic resins, maleicresins, alkyd resins, polyamide resins, phenol resins, petroleum resins,urethane resins, epoxy resins, acrylate resins, butyral resins, melamineresins, epoxy resins, vinyl chloride resins, vinylidene chloride resins,cellulose resins, vinyl resins, unsaturated polyester resins, celluloseresins, etc. These resins may be used alone or in combination of two ormore.

[0124] Examples of mixtures include combination pigments, organicpigments, inorganic pigments and additives such as varnishes, reducer,compounders, ultra varnishes, gelling agents, drying promoter,antioxidants, preventer for transmission of ink to nack, lubricants,surface active agent, etc. Further example include dripping preventor,viscosity adjusting agent, sedimentation preventors, cross-linkingagents, curing agents, leveling agents, defoaming agents, plasticizers,antiseptic agents, antifungal agents, ultraviolet stabilizers, fillers,etc.

[0125] Examples of combination pigments are extender pigments;precipitated barium sulfate; precipitated calcium carbonate; aluminawhite; magnesium carbonate and white carbon; white pigments such astitanium oxide, zinc oxide, etc.; black pigments such as carbon black;yellow pigments such as chrome yellow, disazo yellow, Hansa yellow; redpigments such as brilliant carmine 6B, lake red C, permanent red F5R,Rhodamine Lake, etc.; blue pigments such as phthalocyanine blue,Victoria Blue Lake, Prussian Blue; orange pigments such as chromevermilion, disazo orange; green pigments such as phthalocyanine green,etc.; violet pigments such as methyl violet lake, dioxazine violet,etc.; other pigments such as isoindolinone, benzimidazoline, condensedazo, quinacdrine, etc.; composite oxide pigments; graphite; mica (e.g.,white mica, gold mica, synthetic mica, fluorine tetravalent siliconmica, etc.); metal oxide coated mica (e.g., titanium oxide coated mica,titanium dioxide coated mica, (hydrated) iron oxide coated mica, micacoated with iron oxides and titanium oxides, mica coated with lowerorder titanium oxides); metal oxide coated graphite (e.g., titaniumdioxide coated graphite, etc.); thin-platelet like alumina; metal oxidecoated alumina (e.g., dioxide coated alumina., iron oxide coatedthin-platelet like alumina, Fe₂O₃ coated thin-platelet like alumina,Fe₃O₄ coated thin-platelet like alumina, interference color metal oxidecoated thin-platelet like alumina, etc.); MIO; metal oxide coated MIO;metal oxide coated silica flakes metal oxide coated alumina; metal oxidecoated glass flakes called optical effect pigments; photochromicpigments thermochromic pigments; holographic pigments called functionalpigments; etc. These inks can be printed on wood, plastic, metal sheetsplato, glass, ceramic, paper, corrugated cardboard, film, sheet cannedgoods, translucent films of reflection for LCDs, etc. When the pigmentsof the present invention in combined with these pigments new hue andcolors are appeared. Especially the pigments according to the presentinvention are suitable for preventing the counterfeiting of securities,tickets, passenger tickets, etc., due to their color travel effect (thehue changes depending on the reviewing angle).

[0126] Moreover, when used in printing inks, it is particularlypreferred to perform a high plane orientation treatment (mentionedabove) on the interference colored pigments having a metallic lusterobtained according to the present invention. Pigments subjected to sucha surface treatment can be mixed with various kinds of printing inks andused for offset printing, gravure printing, screen printing, ultravioletcure printing, and relief and lithographic printing. The use of pigmentswhich have been subject to a high plane orientation treatment as an inksparticularly results in improvement of coloration of interference coloron printed surface and color travel effect by changing the viewing anglecaused thereby and that is prepared for printing for preventing hecounterfeiting.

[0127] Use for Plastics

[0128] In the present invention, when incorporated in plastics, thepigments can be mixed with the resin either directly or after previouslymaking into pellets and then making into various molded products bymeans of extrusion molding, calender molding, blow molding, etc. As tothe resin component, polyolefin-based thermoplastic resins as well asepoxy-based, polyester-based and polyamide (nylon)-based thermoplasticresins can be used. A small amount of pigments can be sufficient toeffectively produce the color effects of the interference coloredpigments with metallic luster of the present invention, e.g., whenforming a multiple layer plastic bottle, the external appearance of thebottle can be made to appear effectively by incorporating the pigmentsin the resin of the outer layer. Especially pigments obtained accordingto the present invention on which an additional orientation planetreatment has been performed are preferred in that they have goodcoloring properties. Naturally, it is possible to use metallic lusterinterference colored pigments related to the present invention on whicha weld-line prevention treatment (e.g., encapsulation, etc.) has beenperformed. The highly anti-corrosive thin-platelet like metal pigmentsand the interference colored pigments having metallic luster obtainedaccording to the present invention can also be used in combination withother pigments. Examples of pigments that can be used in combinationwith the pigments of the present invention include titanium dioxide,calcium carbonate, clay, talc, barium sulfate, white carbon, chromiumoxide, zinc oxide, zinc sulfide, zinc powder, metal powder pigments,iron black, yellow iron oxide, red iron oxide, chrome yellow, carbonblack, molybdate orange, Prussian Blue, ultramarine Blue, cadmium typepigments, fluorescent pigments, soluble azo dyes, insoluble azo dyes,condensed azo dyes, phthalocyanine pigments, condensed polycyclicpigments, composite oxide pigments, graphite, mica (e.g., white mica,gold mica, synthetic mica, fluorine tetravalent silicon mica, etc.),metal oxide coated mica (such as, titanium oxide coated mica, titaniumdioxide coated mica, (hydrated) iron oxide coated mica, mica coated withiron oxides and titanium oxides, mica coated with lower ordered titaniumoxides), metal oxide coated graphite (e.g., titanium dioxide coatedgraphite, etc.), thin-platelet like alumina, metal oxide coated alumina(e.g., dioxide coated alumina, iron oxide coated thin-platelet likealumina, Fe₂O₃ coated thin-platelet like alumina, Fe₃O₄ coatedthin-platelet like alumina, interference color metal oxide coatedthin-platelet like alumina, etc.), MIO, metal oxide coated MIO, metaloxide coated silica flakes metal oxide coated alumina, metal oxidecoated glass flakes called optical effect pigments, photochromicpigments, thermochromic pigments, holographic pigments called functionalpigments, etc.

[0129] Use for Cosmetics

[0130] Examples of use in cosmetics include make-up, hair care products,cosmetic packs, etc. E.g., the pigments can be used in gel, lipstick,foundation (including emulsion, liquid, oil-type emulsions, etc.), cheekrouge, mascara, nail enamel, eyebrow pencil, eye shadow, eyeliner, hairproducts, etc. They can be used in a proportion of 1-100 wt %. E.g., forfoundations 1-50 wt %, for eye shadow 1-80 wt %, for lipstick 1-40 wt %,for nail enamel 0.1-20 wt % can be mentioned.

[0131] Examples of mixed components will be given below. Examples ofcombination pigments include titanium dioxide, calcium carbonate, clay,talc, barium sulfate, white carbon, chromium oxide, zinc oxide, zincsulfide, zinc powder, metal powder pigments, iron black, yellow ironoxide, red iron oxide, chrome yellow, carbon black, molybdate orange,Prussian Blue, ultramarine blue, cadmium type pigments, fluorescentpigments, soluble azo dyes, insoluble azo dyes, condensed azo dyes,phthalocyanine pigments, condensed polycyclic pigments, composite oxidepigments, graphite, mica (e.g., white mica, gold mica, synthetic mica,fluorine tetravalent silicon mica, etc.), metal oxide coated mica (e.g.,titanium oxide coated mica, titanium dioxide coated mica, (hydrated)iron oxide coated mica, mica coated with iron oxides and titaniumoxides, mica coated with lower ordered titanium oxides), metal oxidecoated graphite (e.g., titanium dioxide coated graphite, etc.),thin-platelet like alumina, metal oxide coated alumina (e.g., titaniumdioxide coated alumina, iron oxide coated thin-platelet like alumina,Fe₂O₃ coated thin-platelet like alumina, Fe₃O₄ coated thin-platelet likealumina, interference color metal oxide coated thin-platelet likealumina, etc.), MIO, metal oxide coated MIO, metal oxide coated silicaflakes metal oxide coated alumina, metal oxide coated glass flakescalled optical effect pigments, photochromic pigments thermochromicpigments, holographic pigments called functional pigments, sericite,magnesium carbonate, silica, zeolite, hydroxyapatite, chromium oxide,cobalt titanate, glass beads, nylon beads, silicone beads, etc.

[0132] Examples of organic pigments include red nos. 2, 3, 102, 104,105, 106, 201, 202, 203, 204, 205, 206, 207, 208, 213, 214, 215, 218,219, 220, 221, 223, 225, 226, 227, 228, 230-1, 230-2, 231, 232, 405;yellow nos. 4, 5, 201, 202-1, 202-2, 203, 204, 205, 401, 402, 403, 404,405, 406, 407; green nos. 3, 201, 202, 204, 205, 401, 402; blue nos. 1,2, 201, 202, 203, 204, 205, 403, 404; orange nos. 201, 203, 204, 205,206, 207, 401,402, 403; brown no. 201; violet nos. 201, 401; black no.401.

[0133] Examples of natural colors include salol yellow, carmine,β-carotin, hibiscus color, capsaicin, carminic acid, laccaic acid,gurcumin, riboflavin, shikonin, etc. Further, examples of othercomponents include fats and oils, waxes, surfactants, oxidationinhibitors, UV absorbers, vitamins, hormones, squalanes, liquidparaffins, palmitic acids, stearic acids, bees wax, hydrocarbons ofmyristyl myristate etc., acetone, toluene, butyl acetate, solvents ofacetic esters etc., antioxidants, antiseptic agents, polyhydricalcohols, perfumes, etc. By combining the pigments of the presentinvention with these pigments and components, novel effect colors andfunctions can be found.

[0134] When used in cosmetics, the pigments according to the presentinvention can be used e.g. in compact cakes, in cream, in lipstick,etc.; however, they are particularly effective when used in make-up,characterized in that colors are particularly important. Naturally, itis possible to use interference colored pigments having metallic lusterrelated to the present invention on which a surface treatment (mentionedbefore) has been performed.

[0135] Other Uses

[0136] The pigments of the present invention can be used by combiningwith color toners for copying machines etc. E.g., when it is used as scolor toner for copying machines, a color travel effect is achievedthereby an effect of preventing the counterfeiting can be achieved.

EXAMPLES

[0137] Hereinafter, the present invention is for then described in moredetail by reference to the Examples and comparative Examples, whichhowever are not to intend to limit the present invention.

Example 1

[0138] Preparation of Highly Anti-Corrosive Thin-Platelet like MetalPigments

[0139] 1-a) Treatment with a Phosphoric Acid Compound: SS5588(P)

[0140] 1 g of phosphoric acid (85%) was added to a suspension in which78.2 g of an aluminum paste sample {Sparkle Silver SS5588 (manufacturedby Silberline, effective components: 64%, D50: about 18 μm)} weredispersed in 500 ml acetone, and stirred for 30 minutes at roomtemperature. Thereafter, the suspension was filtered and washed withacetone, this operation was repeated once; and then, the solid partswere filtered and the thin-platelet like metal treated with phosphoricacid compound (SS5588(P)) was obtained. The SS5588 (P) obtained amongthe sample for the following coating.

[0141] 1-b) Hydrated Silicon Oxide Coating: SiO₂/SS5588(P)

[0142] In a round bottom flask equipped with a reflux condenser and anagitator, the thin-platelet like metal, treated with phosphoric acidcompound, obtained in step 1-a) (SS5588(P)) was suspended in 750 ml ofethanol. The suspension was heated to 65° C. after 200 g of water and 20g of a 28% aqueous ammonia solution had been added. Next, a solution of60 g of tetraethoxysilane diluted with 76 ml of ethanol was added to itsmall amounts while stirring. This reaction mixture was stirred for 20hours at 65° C., then filtered from the mother liquid, washed withethanol and dried, the highly anti-corrosive platelet like metalpigments (SiO₂/SS5588(P)) were obtained.

Example 2

[0143] Preparation of Highly Anti-Corrosive Thin-Platelet like MetalPigments

[0144] 2-a) Treatment with a Phosphoric Acid Compound: 550N(P)

[0145] 5 g of monoisodecyl acid phosphoric acid was added to asuspension in which 76 g of an aluminum paste sample {550N (manufacturedby Showa Aluminum Co., Ltd., effective components 65.8%, D50: about 19μm)} were dispersed in 500 ml of acetone and stirred for 30 minutes atroom temperature. Thereafter, the suspension was filtered and washedwith acetone, this operation was repeated once; and then, the solidparts were filtered and the thin-platelet like metal treated withphosphoric acid compound (550N(P)) was obtained. The 550N (P) obtainedamong the sample for the following coating.

[0146] 2-b) Hydrated Silicon Oxide Coating: SiO₂/550N(P)

[0147] In a round bottom flask equipped with a reflux condenser and anagitator, the aluminum treated with phosphoric acid compound, obtainedin step 2-a) (550N(P)) was suspended in 750 ml of ethanol. Thesuspension was heated to 65° C. after 200 g of water and 20 g of a 28%aqueous ammonia solution had been added. Next, a solution of 60 g oftetraethoxysilane diluted with 76 ml of ethanol was added to it whilestirring. This reaction mixture was stirred for 20 hours at 65° C., thenfiltered from the mother liquid, washed with ethanol and dried, thehighly anti-corrosive thin-platelet like metal pigments (SiO₂/550N(P))were obtained.

Example 3

[0148] Preparation of Highly Anti-Corrosive Thin-Platelet like MetalPigments

[0149] 3-a) Treatment with a Phosphoric Acid Compound: SL800(P)

[0150] 5 g of monoisodecyl acid phosphoric acid was added to asuspension in which 66.3 g of aluminum paste sample {SL800 (manufacturedby Showa Aluminum Co., Ltd., effective components 75.4%, D50: about 18μm)} were dispersed in 500 ml of acetone and stirred for 30 minutes atroom temperature. Thereafter, the suspension was filtered and washedwith acetone, this operation was repeated once; and then, the solidparts were filtered and the thin-platelet like metal treated withphosphoric acid compound (SL800 (P)) was obtained. The SL800(P) obtainedamong the sample for the following coating.

[0151] 3-b) Hydrated Silicon Oxide Coating: SiO₂/ SL800(P)

[0152] In a round bottom flask equipped with a reflux condenser and anagitator, the aluminum treated with phosphoric acid compound, obtainedin step 3-a) (SL800 (P)) was suspended in 750 ml of ethanol. Thesuspension was heated to 65° C. after 200 g of water and 20 g of a 28%aqueous ammonia solution had been added. Next, a solution of 60 g oftetraethoxysilane diluted in 76 ml of ethanol was added to it whilestirring. This reaction mixture was stirred for 18 hours at 65° C., thenfiltered from the mother liquid, washed with ethanol and dried, thehighly anti-corrosive platelet like metal pigments (SiO₂/SL800 (P)) wereobtained.

Example 4

[0153] Preparation of Highly Anti-Corrosive Thin-Platelet like MetalPigments

[0154] 4-a) Treatment with a Phosphoric Acid Compound: 5422NS(P)

[0155] 1 g of phosphoric acid (85%) was added to a suspension in which66.4 g of aluminum paste sample {5422NS (manufactured by Toyo AluminumCo., Ltd., effective components 75.3%, D50: about 20 μm)} were dispersedin 500 ml of acetone and stirred for 30 minutes at room temperature;thereafter, the suspension was filtered and washed with acetone, thisoperation was repeated once; and then, the solid parts were filtered andthe thin-platelet like metal treated with phosphoric acid compound(5422NS (P)) was obtained. The 5422NS(P) obtained among the sample forthe following coating.

[0156] 4-b) Hydrated Silicon Oxide Coating: SiO₂/5422NS(P)

[0157] In a round bottom flask equipped with a reflux condenser and anagitator, the aluminum treated with phosphoric acid compound, obtainedin step 4-a) (5422NS (P)), was suspended in 750 ml of ethanol. Thesuspension was heated to 65° C. after 200 g of water and 20 g of 28%aqueous ammonia solution had been added. Next, a solution of 60 g oftetraethoxysilane and 2 g of γ-(2-aminoethyl)aminopropyltrimethoxysilanediluted with 76 ml of ethanol was added to it while stirring. Thisreaction mixture was stirred for 18 hours at 65° C., then filtered fromthe mother liquid, washed with ethanol and dried, the highlyanti-corrosive platelet like metal pigments (SiO₂/5422NS (P)) wereobtained.

Example 5

[0158] Preparation of Highly Anti-Corrosive Thin-Platelet like MetalPigments

[0159] 5-a) Treatment with a Boric Acid Compound: 5422NS(B)

[0160] 0.3 g of boric acid was added to a suspension in which 66.4 g ofan aluminum paste sample {5422NS (manufactured by Toyo Aluminum Co.,Ltd., effective components 75.3%, D50: about 20 μm)} were dispersed in500 ml of acetone, and stirred for 30 minutes at room temperature;thereafter, the suspension was filtered and washed with acetone, thisoperation was repeated; Thereafter, the solid parts were filtered andthe thin-platelet like metal treated with boric acid compound(5422NS(B)) was obtained. The 5422NS(B) obtained among the sample forthe following coating.

[0161] 5-b) Hydrated Silicon Oxide Coating: SiO₂/5422NS(B)

[0162] In a round bottom flask equipped with a reflux condenser and anagitator, the aluminum with a boric acid compound obtained in step 5-a)(5422NS(B)) was suspended in 750 ml of ethanol. The suspension washeated to 65° C. after 200 g of water and 20 g of 28% aqueous ammoniasolution had been added. Next, a solution of 60 g of tetraethoxysilaneand 2 g of γ-(2-aminoethyl)-aminopropyltrimethoxysilane diluted with 76ml of ethanol was added to it while stirring. This reaction mixture wasstirred for 18 hours at 65° C., then filtered from the mother liquid,washed with ethanol and dried, the highly anti-corrosive thin-plateletlike metal pigments (SiO₂/5422NS (B)) were obtained.

Example 6

[0163] Preparation of the Interference Colored Pigments having MetallicLuster: TiO₂/SiO₂/5422NS(P)

[0164] 50 g of the highly anti-corrosive thin-platelet like metalpigments SiO₂/5422NS(P) obtained in Example 4-b) were suspended in 1liter of water and heated to 75° C. under stirring. 50.6 g of SnCl₄.5H₂Osolution (SnCl₄.5H₂O, 29 g/liter) were dropped to this suspension whilebeeping PH at 1.8 using sodium hydroxide of 32 wt %. Next, titaniumtetrachloride solution (TiCl₄, 448 g/liter) was dropped into thesuspension while keeping the pH at 1.8 using sodium hydroxide of 32 wt%. The reaction was finished until at the green color was reached. Fromthe suspension, the solid parts were filtered, washed with water, thendried and calcined, the interference colored pigments having metallicluster (TiO₂/SiO₂/5422NS(P)) were obtained. It was confirmed by X-raydiffraction that the hydrated titanium layer of the coating was a rutiletype. 1 weight part of this powder was dispersed in 9 weight parts of anacryl-modified nitrocellulose lacquer and coated on a black and whitepaper with an applicator (bar coater #20). The hue change (color traveleffect) depended on viewing angle was appeared from the measurementusing the goniospectrophotometer GCMS-3 (manufactured by Murakami ColorResearch Laboratory). The results of the color measurement is shown inTable 1.

[0165] (Table 1) TABLE 1 Result of color measurement bygoniospectrophotometer Incident angle/ observation Luster Hue angle (L*)a* b* Chromaticity angle 45/0 47.07 3.05 −11.82 12.21 284.47 45/10 62.640.76 −6.58 6.63 276.63 45/20 90.40 −3.34 2.78 4.34 140.21 45/30 132.64−8.73 15.32 17.63 119.67 45/40 177.62 −13.28 24.60 27.96 118.37 45/50182.69 −13.51 23.92 27.47 119.47 45/60 143.38 −10.18 17.57 20.31 120.0945/70 102.65 −4.73 9.86 10.93 115.63

[0166] From the result of the table, when angle of color variation waschanged, hue changes were observed in such a way to the state from thechromaticity 27.96 at 45/40 and hue angle of 118° (greenish yellow) tothe chromaticity of 12.21 at 45/0 and hue angle of 284° (reddish blue),whereby a color travel effect was confirmed.

Comparative Example 1

[0167] Preparation of SiO₂/5422NS

[0168] 66.4 g of the aluminum paste {5422NS (manufactured by ToyoAluminum Co., Ltd., effective components 75.3%, D50: about 20 μm)} weredispersed in 500 ml of acetone, the suspension was stirred for 30minutes at room temperature, then filtered, washed with acetone, andthis operation was repeated once; and thereafter, the solid parts wereobtained by filtering. In a round bottom flask equipped with a refluxcondenser and an agitator, the solid parts were suspended in 750 ml ofethanol. The suspension was heated to 65° C. after 200 g of water and 20g of a 28% aqueous ammonia water solution had been added. Next, asolution of 60 g of tetraethoxysilane diluted with 76 ml of ethanol wasadded to it while stirring. This reaction mixture was stirred for 18hours at 65° C., then filtered from the mother liquid, washed withethanol and dried, and SiO₂/5422NS was obtained

Comparative Example 2

[0169] Preparation of TiO₂/SiO₂/5422NS

[0170] 50 g of the hydrated silicon oxide coated SiO₂/5422NS powderobtained in Comparative Example 1 was suspended in 1 liter of water andheated to 75° C. under stirring. 50.6 g of SnCl₄.5H₂O solution(SnCl₄.5H₂O, 29 g/liter) were dropped into this suspension while keepingpH at 1.8 using sodium hydroxide of 32 wt %. Next, titaniumtetrachloride solution (TiCl₄, 448 g/liter) was dropped into thesuspension obtained while keeping pH at 1.8 using sodium hydroxide of 32wt %. The reaction was finished until green color was reached. The solidparts were filtered from the suspension, washed with water dried andcalcined. The interference colored pigments having metallic lusterTiO₂/SiO₂/5422NS was obtained. It was confirmed by X-ray diffractionthat the hydrated titanium oxide in the coated layer was a rutile type.1 weight part of this powder was dispersed in 9 weight parts of anacryl-modified nitrocellulose lacquer and coated on a black and whitepaper with an applicator (bar coater #20). Result of the colormeasurement using a goniorespectrophotometer GCMS-3 (manufactured byMurakami Color Research Laboratory) are shown in Table 2.

[0171] (Table 2) TABLE 2 Result of color measurement bygoniorespectrophotometer Incident angle/ observation Luster Hue angle(L*) a* b* Chromaticity angle 45/0 46.35 −1.20 3.64 3.83 108.27 45/1064.43 −3.43 9.17 9.79 110.52 45/20 89.49 −5.69 15.15 16.19 110.56 45/30123.62 −8.38 21.75 23.31 111.06 45/40 164.98 −8.38 25.02 26.39 108.5045/50 167.99 −7.99 21.96 23.36 109.99 45/60 124.47 −6.40 17.54 18.67110.03 45/70 91.50 −3.41 13.30 13.73 104.40

[0172] From the result of the table, when the maximum chromaticity at45/40 and hue angle 1090 (greenish yellow) was 26.39, even when angle ofvation was changed, the change in hue angle was narrow (from 104° to111° (greenish yellow)), whereby no color travel effect was observed.

[0173] Anti-Corrosion Test (Measurement of the Amount of GeneratedHydrogen Gas):

[0174] 1 g of each sample was dispersed in 100 g of warm water (75° C.)of pH of 1.8 adjusted by hydrochloric acid (HCl), and the temperature ofthis suspension was kept at 75° C. under stirring. After predeterminedeach time, the amount of generated hydrogen (H₂) from the suspension wasmeasured. Measurements were taken during 120 minutes. A comparisonbetween untreated Al flakes (the surface treatment agent was removed bywashing), Al flakes (P) {treated with phosphoric acid compounds only(first stage treatment)}, and SiO₂/Al flakes (P) {coated with hydratedsilicon oxide after being treated with phosphoric acid compounds (firststage treatment+second stage coating)} is shown in FIG. 3, 1-4. Similarcomparison among Al-flakes treated by boric acid compounds (Example 5)instead of by phosphoric acid compounds in shown in FIG. 5.

[0175]FIG. 1 shows a comparison of the amount of generated hydrogen gasin the case of use of SS5588 among the untreated SS5588, SS5588(P) andSiO₂/SS5588(P).

[0176] Here, SS5588(P) was obtained in 1-a) of Example 1 andSiO₂/SS5588(P) was obtained in Example 1-b) of Example 1. An amount ofgenerated hydrogen gas was very little for SiO₂/SS5588(P) according tothe present invention.

[0177]FIG. 2 shows a comparison of the amount of generated hydrogen gasin the case of use of 550N among the untreated 550N, 550N(P) andSiO₂/550N(P).

[0178] Here, 550N(P) was obtained in 2-a) of Example 2 and SiO₂/550N(P)was obtained in 2-b) of Example 2. No hydrogen gas was generated withthe SiO₂/550N(P) according to the present invention.

[0179]FIG. 3 shows a comparison of the amount of generated hydrogen gasin the case of use of SL800 among the untreated SL800, SL800(P) andSiO₂/SL800(P).

[0180] Here, SL800(P) was obtained in 3-a) of Example 3 andSiO₂/SL800(P) was obtained in 3-b) of Example 3. Hydrogen gas was rarelygenerated with the SiO₂/SL800(P) according to the present invention.

[0181]FIG. 4 shows a comparison of the amount of generated hydrogen gasin the case of use of 5422NS among the untreated 5422NS, 5422NS(P),SiO₂/5422NS(P) and SiO₂/5422NS.

[0182] 5422NS(P) was obtained in 4-a) of Example 4, SiO₂/5422NS(P) wasobtained in 4-b) of Example 4 and SiO₂/5422NS was obtained inComparative Example 1 (flakes treated only by the second stage coating,i.e. the “hydrated silicon oxide coating”, without subject to the firststage treatment, i.e. the “phosphoric acid compound treatment”).Hydrogen gas was rarely generated with the SiO₂/5422NS(P) flakesaccording to the present invention. As for 5422 NS(P) treated only witha large amount of hydrogen gas was generated within a short period oftime, phosphoric acid compound (the first stage treatment) and muchhydrogen gas was also generated for the SiO₂/5422NS after the timelapsed.

[0183]FIG. 5 shows a comparison of the amount of generated hydrogen gasin the case of use of 5422NS among the untreated 5422NS, 5422NS(B),SiO₂/5422NS(B) and SiO₂/5422NS.

[0184] Here, 5422NS(B) was obtained in 5-a) of Example 5, SiO₂/5422NS(B)was obtained in 5-b) of Example 5 and SiO₂/5422NS was obtained inComparative Example 1 (flakes treated only by the second stage coating,i.e. the “hydrated silicon oxide coating”, without subject to the firststage treatment, i.e. the “boric acid compound treatment”). Hydrogen gaswas rarely generated with the SiO₂/5422NS(B) according to the presentinvention. As for 5422 NS(B) treated only with boric acid compound(first stage treatment), a large amount of hydrogen gas was rarelygenerated within a short period of time and, much hydrogen gas was alsogenerated with the SiO₂/5422NS after the time lapsed.

[0185] Measurement of the Specific Surface Area

[0186] The specific surface area was measured with a fully-automated gasadsorption analyzer (Autosorb 6 manufactured by QuantaChrome). Theresults are shown in Table 3.

[0187] (Table 3) TABLE 3 Measurement of the specific surface area SampleSpecific surface area A(m²/g) Untreated 5422NS 2.24 SiO₂/5422NS(P)(Example 4-b) 3.01 SiO₂/5422NS (Comparative Example 1) 8.32

[0188] It was demonstrated in table 3 the two stage treatment where atreatment with a phosphoric acid compounds and a hydrated silicon oxidecoating were combined according to the present invention gave lessincrease in the specific surface area, namely, the coated layer wasdense and smooth as compared with comparative Examples. It was furtherdemonstrated in FIG. 4 that the product according to said two stagestreatments showed better anti-corrosive property as compared with thecase of a coated layer with hydrated silicon oxide only.

[0189] Dispersibility Evaluation

[0190] The dispersibility was evaluated by means of the hiding power.The more hiding power, the higher dispersibility is. Hiding power wascalculated in such a way that 1 weight part of the samples was dispersedin 9 weight parts of an acryl-modified nitrocellulose lacquer and coatedon a black and white paper with an applicator (bar coater #20), thereflectance of the samples was measured using a color meter (CR-300manufactured by Minolta Camera Co., Ltd.) and the hiding power wascalculated by the formula below. The results are shown in Table 4.

Hiding power=100×(Diffuse reflectance of coated film on Blackground45°/0°)/(Diffuse reflectance of coated film on white ground 45°/0°)

[0191] (Table 4) TABLE 4 Hiding power Sample Hiding power (%) 5422NS99.6 SiO₂/5422NS(P) (Example 4-b) 96.5 SiO₂/5422NS (ComparativeExample 1) 79.1

[0192] It was demonstrated by the above results that the highlyanti-corrosive thin-platelet like metal pigments according to thepresent invention, where thin-platelet like metal substrate were treatedwith phosphoric acid compound combined with hydrated silicon oxidecoating layer on the surface thereof, is consisted of dense coatedlayers due to small specific surface area, and had a highdispersibility, due to high hiding power.

[0193] Specific examples for the use will now be shown as hereafter.

Use Example 1 Use Examples for Paint

[0194] Paint based on pearlescent pigments:

[0195] (Composition A) Acrydick 47-712 70 weight parts Super BeckamineG821-60 30 weight parts

[0196] (Composition B) Samples of Examples 1-6 10 weight partsPearlescent pigments 10 weight parts

[0197] (Composition C) Ethyl acetate 50 weight parts Toluene 30 weightparts n-butanol 10 weight parts Solvesso #150 40 weight parts

[0198] 100 weight parts of Composition A were mixed with 20 weight partsof Composition B and then diluted with Ford Cup #4 for a viscosity of12-15 seconds suitable for spray-coating with Composition C, whereupon abasecoat was formed by spray coating.

[0199] Clear paint: Acrydic 44-179 14 weight parts  Super BeckamineL117-60 6 weight parts Toluene 4 weight parts Methyl isobutyl ketone(MIBK) 4 weight parts Butyl cellosolve 3 weight parts

[0200] This composition was coated on the above pearlescent coating,dried at 40° C. for 30 minutes, air-dried at room temperature and bakedat 130° C. for 30 minutes.

[0201] It was confirmed that the paint films formed with compositionscontaining samples of Examples 1-5 had a good metallic luster and thatthe paint film formed with the composition containing a sample ofExample 6 had a high brightness, had a high chromaticity and a colortrevel effect.

Use Example 2 Use Example for Plastic

[0202] High density polyethylene (pellets) 100 weight parts Samples ofExamples 1-6 1 weight part Magnesium stearate 0.1 weight parts Zincstearate 0.1 weight parts

[0203] These components were dry-blended and formed by injectionmolding.

[0204] It was confirmed that the moldings containing samples of Examples1-5 had a good metallic luster and that the molding containing a sampleof Example 6 had high brightness, high chromaticity and a color traveleffect.

Use Example 3 Use Example for Ink

[0205] CCST medium (nitrocellulose resin) 10 weight parts Samples ofExamples 1-6  8 weight parts

[0206] The solvent NC 102 was added to the ink composition blended fromthe above components, and the ink was prepared with a viscosity of 20seconds with Zahn Cup No. 3.

[0207] It was confirmed that the prints obtained with inks containingsamples of Examples 1-5 had a good metallic luster and that the printobtained with an ink containing a sample of Example 6 had highbrightness, high chromaticity and a color travel effect.

Use Example 4 Use Example for Cosmetics

[0208] Use example for compact powder: Talc 50 weight parts Samples ofExamples 1-6 25 weight parts Color pigments  5 weight parts Isopropylmyristate a suitable amount Magnesium stearate  2 weight parts

[0209] Use example for a foundation: Talc  38 weight parts Samples ofExamples 1-6  25 weight parts Mica (8 μm)  10 weight parts Magnesiumstearate   3 weight parts Nylon powder 12   8 weight parts Yellow ironoxide 1.9 weight parts Red iron oxide 0.8 weight parts Titanium oxide1.0 weight part  Mineral oil    a suitable amount (caprylic acid, capricacid) triglyceride 3.3 weight parts Butylparaben 0.1 weight parts

28. Highly anti-corrosive thin-platelet like metal pigments comprising,on the surface of thin-platelet like metal substrates treated withphosphoric acids compounds and/or boric acids compounds, one or morecoated layer containing one or more hydrated metal oxides of one or moremetals selected from the group consisting of silicon, aluminum,zirconium, titanium and tin.
 29. The highly anti-corrosive thin-plateletlike metal pigments according to claim 28, wherein the thin-plateletlike metal substrates are metallic pigments having metallic luster. 30.The highly anti-corrosive thin-platelet like metal pigments according toclaim 29, wherein the metallic pigments having metallic luster is anyone of aluminum flakes, titanium flakes, gold flakes, silver flakes,copper-zinc alloy flakes, stainless steel flakes or bronze flakes. 31.The highly anti-corrosive thin-platelet like metal pigments according toclaim 28, wherein the hydrated metal oxides are hydrated silicon oxides.32. The highly anti-corrosive thin-platelet like metal pigmentsaccording to claim 28, wherein the hydrated metal oxides are prepared bythe sol-gel method.
 33. The highly anti-corrosive thin-platelet likemetal pigments according to claim 32, wherein the sol-gel method isperformed by hydrolysis of metal alkoxide.
 34. The highly anti-corrosivethin-platelet like metal pigments according to claim 33, wherein thehydrolysis of metal alkoxide is performed by using a basic catalyst. 35.The highly anti-corrosive thin-platelet like metal pigments according toclaim 28, wherein the amount of phosphoric acids compounds and/or boricacids compounds, is corresponding to 0.0001-0.1 g as P₂O₅ and/or B₂O₃per unit surface area (m²) of thin-platelet like metal substrates andthe amount of metal compounds used for preparing a hydrated metal oxidecoated layer, is corresponding to 0.01-1.0 g as SiO₂, Al₂O₃, ZrO₂, TiO₂and SnO₂ per unit surface area (m²) of thin-platelet like metalsubstrates.
 36. The preparing method of highly anti-corrosivethin-platelet like metal pigments, wherein dispersing the thin-plateletlike metal substrates in a polar organic solvent, and the methodcontains the processes of 1) adding phosphoric acid compounds and/orboric acid compounds thereto stirring it, and accordingly treating itssubstrate, 2) preparing coated layer of a hydrated metal oxide on thesurface of said substrates by the sol-gel method
 37. The preparingmethod according to claim 36, wherein the sol-gel method is performed byhydrolysis of a metal alkoxide solution that is dissolved in a polarorganic solvent.
 38. The preparing method according to claim 36, whereinthe metal composing the coated layer of hydrated metal oxide are one ormore metals selected from the group consisting of silicon, aluminum,tin, zirconium and titanium.
 39. The preparing method according to claim37, wherein the metal alkoxide solution is added after adding of waterand a catalyst.
 40. The preparing method according to claim 37, whereinthe metal alkoxide solution is added at the same time as an aqueoussolution containing a catalyst.
 41. The preparing method according toclaim 37, wherein the aqueous solution containing a catalyst is addedafter addition of the metal alkoxide solution.
 42. The production methodaccording to claim 39, wherein the catalyst is a basic catalyst. 43.Interference colored pigments having metallic luster, wherein thesurface of the highly anti-corrosive thin-platelet like metal pigmentaccording to claim 28 is further coated with a secondary hydrated metaloxide layer comprising one or more layers.
 44. The interference coloredpigments having metallic luster according to claim 43, wherein thesecondary coated layer of hydrated metal oxides is prepared a wetprocess method, a chemical vapor deposition process method or a physicalvapor deposition process method.
 45. The interference colored pigmentshaving metallic luster according to claim 44, wherein the secondarycoated layer of hydrated metal oxides is prepared by a wet processmethod.
 46. The interference colored pigments having metallic lusteraccording to claim 43, wherein the secondary coated layer of hydratedmetal oxides is the coated layers containing one or more hydrated metaloxides of one or more metals selected from the group consisting oftitanium, aluminum, zirconium, tin, zinc, iron, chromium, cobalt,silicon and boron.
 47. The interference colored pigments having metallicluster according to claim 43, wherein the secondary coated layers ofhydrated metal oxides are multi-coated layer having different hydratedmetal oxides.
 48. The interference colored pigments having metallicluster according to claim 47, wherein the secondary coated layers ofhydrated metal oxides are alternately multi-coated layers of hydratedmetal oxides having a high refractive index and having a low refractiveindex.
 49. The use of the highly anti-corrosive thin-platelet like metalpigments according to claim 28 or the interference colored pigmentshaving metallic luster in the invention paints, powder coatings and itspainting layers, inks, security printing inks, plastics, pelletsmoldings, and cosmetics.
 50. A composition containing the highlyanti-corrosive thin-platelet like metal pigments according to claim 28or the interference colored pigments having metallic luster of theinvention.
 51. A composition according to claim 50 containing furtherone or more compounds selected from the group of combination pigment,organic pigment, and natural colors.
 52. A composition according to theclaim 51 characterized in that the combination pigment is one or moreselected from the group of metallic pigment, metal oxide coated mica,metal oxide coated thin-platelet like alumina, optical effect pigment,and functional pigment.
 53. A paint containing the highly anti-corrosivethin-platelet like metal pigments according to claim 28 or theinterference colored pigments having metallic luster in the invention.54. A paint according to the claim 53 characterized in furthercontaining a combination pigment.
 55. A paint according to claim 54characterized in that the combination pigment is one or more selectedfrom the group of metallic pigment, metal oxide coated mica, metal oxidecoated thin-platelet like alumina, optical effect pigment, andfunctional pigment.
 56. A paint according to claim 53 characterized inbeing a powdery paint.
 57. A paint according to claim 53 characterizedin being an aqueous system (=water-borne) paint.
 58. An ink containingthe highly anti-corrosive thin-platelet like metal pigments according toclaim 28 or the interference colored pigments having metallic luster ofthe invention.
 59. An ink according to the claim 58 characterized infurther containing a combination pigment.
 60. An ink according to claim59 characterized in that the combination pigment is one or more selectedfrom the group of metallic pigment, metal oxide coated mica, metal oxidecoated thin-platelet like alumina, optical effect pigment, andfunctional pigment.
 61. An ink according to claim 58 characterized inbeing an aqueous system (=water-borne) ink.
 62. A plastic containing thehighly anti-corrosive thin-platelet like metal pigments according toclaim 28 or the interference colored pigments having metallic luster ofthe invention.
 63. A plastic according to the claim 62 characterized infurther containing a combination pigment.
 64. A plastic according toclaim 63 characterized in that the combination pigment is one or moreselected from the group of metallic pigment, metal oxide coated mica,metal oxide coated thin-platelet like alumina, optical effect pigment,and functional pigment.
 65. A painted layer that is coated with thepaint according to claim
 53. 66. A painted layer according to claim 65comprising at least two layers having further clear coated layerthereabove.
 67. A printing obtained from the ink according to claim 58.